David Phelps was issued a locker and an opportunity when he reported to camp with the Yankees this spring, but the 25-year-old right-hander couldn't have guessed what an impact he'd have on the club's season.

Utilized both as a starter and a reliever at the big league level, Phelps has been among the most impressive products of the Yankees' farm system this season. As MLB.com re-ranked New York's prospects list, Phelps jumped from his original No. 12 ranking this spring to graduate into a bona fide big league talent.

"It's one thing to be a starter your whole career and then start and be successful," Yankees manager Joe Girardi said. "But to be able to be a starter, be thrown into the bullpen, be a long guy, not necessarily be on your normal routine, and then at times be a one-inning guy and do a lot of different things, that's been impressive for me."

Overall, it has not been a banner year for the Yankees' system; several talented players have taken steps back in their development, as injuries and inconsistency stalled their progress through the chain.

Those setbacks were reflected as the Bronx Bombers' system dropped in the overall rankings among the 30 clubs, though avid followers of the Yanks' farm system have also found reasons to be encouraged this year with the progress of several up-and-coming players.

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Graduated

New York had one player from the preseason Top 20 list stick at the big league level this year: Phelps, who is scheduled to start on Thursday as New York begins a four-game showdown for first place with the Orioles in Baltimore.

Phelps, 25, will be making his eighth Major League start, having combined to go 1-2 with a 3.79 ERA in those outings. He also made 19 relief appearances for the Yankees, providing versatility for the team.

"It's great. It's what I've done my whole career," Phelps said of starting. "It's what I did through college, through my whole baseball career from Little League, I've started. It's great to go out there in this type of game and give your team a chance to win."

Dropped off

A lower back strain kept catcher Austin Romine off the field for most of 2012, forcing him to slip out of the Yankees' Top 20 from the No. 7 spot he occupied this spring. Romine didn't play in a game until July and finally did make it to Triple-A Scranton/Wilkes-Barre, but it was largely a lost year for the 22-year-old.

It was also a step backward for shortstop Cito Culver, the Yankees' first-round Draft pick in 2010, who was ranked No. 9 coming into this year but batted just .215 in 122 games at Class A Charleston this year.

Other Yankees Minor Leaguers falling out of the Top 20 include catcher J.R. Murphy, second baseman Claudio Custodio, outfielder Ben Gamel, infielder David Adams and right-hander Bryan Mitchell.

New faces

The newcomers on the Yankees' Top 20 list are paced by right-hander Ty Hensley, the club's No. 1 selection in the 2012 First-Year Player Draft, who clocks in at the No. 6 spot in the September re-rankings.

After signing a pro contract with a $1.2 million bonus in July, the 18-year-old Hensley said that he plans to be pitching at Yankee Stadium by age 21.

"It's definitely still my goal," Hensley said. "That's what I plan on doing. I've got a good group of people behind me and I think it's definitely within reach."

Outfielder Tyler Austin gained 12 spots and is now ranked as the Yankees' No. 3 prospect after a monster season spent mostly with Class A Charleston and Class A Tampa (.320 BA, .405 OBP, .598 SLG), despite missing about a month with a concussion.

Right-hander Dellin Betances fell 15 spots and is now ranked at No. 17 after a wild and injury-plagued season that saw him demoted to Double-A Trenton. Jose Campos, who was acquired from the Mariners in the Michael Pineda trade, fell 11 slots to No. 16 and suffered a season-ending elbow injury. Shortstop Ravel Santana also fell eight spots to No. 20.

Top 100 representation

Coming into the season, MLB.com judged the Yankees to rank ninth with 225 prospect points among their Top 100 representatives -- fourth among American League clubs, behind the Mariners, Royals and Rangers -- but the re-rankings now have them with 152 points, one slot behind the Mets (170) at No. 18 overall.

Left-hander Manny Banuelos was ranked 13th in baseball overall, but fell 85 spots to No. 98, though he is still the Yankees' fourth-ranked prospect. Betances dropped out of the Top 100 from No. 41, while catcher Gary Sanchez moved up 12 spots to No. 41. Outfielder Mason Williams shot up 26 spots from No. 73 to No. 26, while Austin is ranked No. 66 in baseball.

Bryan Hoch is a reporter for MLB.com. Follow him on Twitter @bryanhoch and read his MLBlog, Bombers Beat. This story was not subject to the approval of Major League Baseball or its clubs.